Recommended rendering resolution for 7" Rift is 2170x1360. The final image for each eye is fisheye distorted, and if you resample down from that size, then you will still have sufficiently max detail at the center.

Create a body model to have visual identity for the player. They like to see hands and body. Or maybe even have mirrors to see yourself.

UI needs rethinking. Where to put it, so it's visible, but not in the way? Integrate to game world if you can. But if you have non-integrated UI, then best option is still to render the UI in 3D.

You need to decide how to handle Z depth. If the 3D UI is too close, eyes can take half a sec to adjust to look at it. And most of the time you see the UI in double when you look at far away.

One solution is to use different depths. E.g. paint a reticle on the target you're looking at. But things like scoreboards still need to be handled differently.

Match vestibular senses with the in-game camera view. I think this links with the head tilt point mentioned above. It can even reduce simulator sickness. (Well, still, there's only so much you can do - for example you would need a rotating simulator chair to properly simulate feeling of acceleration.)

Cutscenes & movies need headlook camera control (sort of obvious). Adding headlook to everything, even loading screens, does a lot for immersion.

Simple things are now new experiences, for example flying or falling.

I ended up interlacing viewing of the videos above by checking out some stuff from Wikipedia.

http://en.wikipedia.org/wiki/Motion_simulatorAs a sidetrack about the vestibular senses, I read the Motion simulator article. It suggests that if you would have an actual motion simulator (rotating chair or so), it should move about 130ms before visual motion to maximize fidelity. It also says that brain can't perceive slow and gradual enough motion in vestibular system (~2 degrees/sec), which is actually used by motion simulators to return to neutral position without you noticing. I guess this also gives a reason why moving slowly causes less simulator sickness.

I kinda get the vibe we're talking "bad good" here, in a way graphics, for instance, can be "good bad graphics" (lo-res blocky crap that still looks good).. some threshold has been crossed and people care about things they wouldn't have cared if it was worse.